I...don't think anyone is super OP. I've fought an army of Karins with Vega and I never felt like I was at any kind of disadvantage
I will say ~as of right now~ Necalli and Rashid feel underpowered compared to the rest of the cast but it's so early at this point that there's probably some tech people haven't discovered yet. And, as everyone has said, shit's going to change a lot between now and March.
Man, Rashid is fucking stupid good.